旋转体体积——圆盘积分法探索与实践

旋转体体积——圆盘积分法探索与实践
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2019-06-03 20:00
① 本范例通过动态交互方式,直观演示了平面曲线绕坐标轴旋转形成立体(旋转体)的过程,并利用圆盘法(Disk method)计算其体积。② 核心数学概念包括定积分、旋转体体积公式、函数图像与三维曲面,以及参数选择对体积的影响。③ 作图要点:使用GeoGebra的Surface命令生成旋转曲面,Integral/IntegralBetween计算定积分,Rotate实现旋转,Textfield和Slider(如CampoInserimento)提供交互输入,Point、Segment、Circle等辅助构造图形,并通过SelectedIndex切换不同函数或选项。④ 适合高中至大学阶段的微积分教学,尤其适用于直观理解旋转体体积公式的推导,也可用于学生自主探索不同函数旋转后的体积变化。

GeoGebra 命令及参数

  1. Textfield(f) → CampoInserimento1
  2. Textfield(a) → CampoInserimento2
  3. Textfield(b) → CampoInserimento3
  4. Point(g) → A
  5. Segment(AX, A) → h
  6. Segment(D, B) → i
  7. Segment(E, C) → j
  8. Surface(t, (g(t) * cos(u)), (g(t) * sin(u)), t, a, b, u, 0, α) → SupX
  9. Integral(f, a, b) → int
  10. Surface(t, (u * f(t)), 0, t, a, b, u, 0, 1) → Integr3D
  11. Rotate(Integr3D, α, xAxis) → Integr3D'
  12. CurveCartesian(t, (f(t) * cos(α)), (f(t) * sin(α)), t, a, b) → RotX
  13. Rotate(A, α, xAxis) → A'
  14. Rotate(E, α, xAxis) → E'
  15. Rotate(D, α, xAxis) → D'
  16. CurveCartesian(x(C), y(C) + (y(E) * cos(t)), z(C) + (y(E) * sin(t)), t, 0, α) → Cfr2x
  17. CurveCartesian(x(B), y(B) + (y(D) * cos(t)), z(B) + (y(D) * sin(t)), t, 0, α) → Cfr1x
  18. SelectedIndex(scelte) → is
  19. Segment(AY, A) → n
  20. Rotate(Integr3D, (-α), yAxis) → Integr3D'_1
  21. CurveCartesian((x(B) * cos(t)), 0, (x(B) * sin(t)), t, 0, α) → c
  22. CurveCartesian((x(C) * cos(t)), 0, (x(C) * sin(t)), t, 0, α) → e
  23. CurveCartesian((a * cos(t)), y(D), (a * sin(t)), t, 0, α) → k
  24. CurveCartesian((b * cos(t)), y(E), (b * sin(t)), t, 0, α) → l
  25. Circle(AX, h, xAxis) → q
  26. Circle(AY, n, yAxis) → r
  27. Circle(B, i, xAxis) → xSx
  28. Circle(C, j, xAxis) → s
  29. Segment(DY, D) → p
  30. Segment(EY, E) → t
  31. Circle(DY, p, yAxis) → yb
  32. Circle(EY, t, yAxis) → ya
  33. Surface((u * cos(v)), f(u), (u * sin(v)), u, a, b, v, 0, α) → SupY
  34. CurveCartesian(t, 0, 0, t, a, b) → xCorCir
  35. Mirror(Surface[xCorCir, α, yAxis], z = 0) → CorCir
  36. Rotate(g, (-α), yAxis) → RotY
  37. Rotate(xCorCir, (-α), yAxis) → RotAB
  38. CurveCartesian(b, t, 0, t, 0, y(E)) → xOut
  39. Mirror(Surface[xOut, α, yAxis], z = 0) → Out
  40. Max(y(E), y(D)) → alto
  41. Min(y(D), y(E)) → basso
  42. Surface(t, (u * fa(t)) + ((1 - u) * fb(t)), 0, t, 0, a, u, 0, 1) → Int3Dsx
  43. Surface(t, (u * If[alto ≟ y(E), fa(t), f(t)]) + ((1 - u) * If[alto ≟ y(E), f(t), fb(t)]), 0, t, a, b, u, 0, 1) → Int3Ddx
  44. Rotate(Int3Ddx, (-α), yAxis) → Int3Ddx'
  45. Rotate(Int3Dsx, (-α), yAxis) → Int3Dsx'
  46. Circle(DY, a, yAxis) → tappo2
  47. Circle(EY, b, yAxis) → tappo1
  48. IntegralBetween(fa, fb, 0, a) → intsx
  49. IntegralBetween(If[y(E) ≥ y(D), fa, f], If[y(E) ≥ y(D), f, fb], a, b) → intdx

AI 绘图提示语参考

绘制一个旋转体,展示平面曲线绕轴旋转形成的立体图形,并用积分法计算其体积。图形包含函数图像、旋转轴、生成的三维表面,以及用于输入函数和参数的滑动条。通过动态调整参数,观察函数变化对旋转体体积的影响,并可视化积分计算过程。
以上提示语为根据原始绘图命令整理而来,仅供参考。